every nfl player who plays for a significant period of time does. and the problem was there was no real protocol in the nfl for diagnosing concussions for a long time. this is a situation where a guy who would just shake it off and go back on the field. it's only in the last couple of years the nfl has gotten really serious about diagnosing concussions on the field and preventing players from coming back on the field after they've suffered injury. so, you know, this is just an issue that is going to be plaguing the nfl for a long time. we've got 4,000 players suing the league, former players suing the league based on their medical condition right now. >> greta: now, in terms of him, i mean, you said that he's always got a smile on his face, every time we see a picture of him. the family say anything peculiar about it over the period of time. >> he retired a few years ago, and the normal life of a celebrity athlete were difficult. there were some issues where he was, you know, apparently sleep deprived and behaving somewhat erratically. the problem i